Cross-Layer Information to Enhance TCP-AP Congestion Control in Wireless Networks

The dynamic and instability of wireless links make congestion control an important research subject in wireless networks. It is important to define strategies that accurately evaluate the characteristics of the wireless links and what can be used by congestion control protocols. It is known that TCP experiences serious performance degradation problems in wireless networks. It has been showed that new variants of TCP, defined fo wireless congestion control, such as TCP-AP, do not evaluate accurately the capacity and available link bandwidth in wireless networks. In this paper, we propose a new congestion control protocol for wireless networks, based in TCP-AP and in a new cross layer information (CLI). We name the proposed protocol TCP-AP with CLI. It relies on the MAC layer information gathered by a method that accurately estimates the available bandwidth and the path capacity over a wireless network path and introduces the concept of node count fair bandwidth share effect. The new congestion control mechanism is evaluated in different scenarios, in wireless mesh and ad-hoc networks, and compared against several approaches for wireless congestion control. It is shown that TCP-AP with CLI outperforms the base TCP-AP, showing its stable behavior and better channel utilization. Keywords—Congestion control, available bandwidth, path capacity, measurements, performance, wireless networks.